Premium
Conformation and ortho steric effects in a series of 2‐(pyrazol‐1‐yl)quinolines
Author(s) -
Singh Shiv P.,
Kumar Dalip,
Kumar Devinder,
Martínez Ana,
Elguero José
Publication year - 1996
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570330219
Subject(s) - chemistry , steric effects , pyrazole , isopropyl , stereochemistry , medicinal chemistry , condensation , computational chemistry , physics , thermodynamics
Nine 2‐(pyrazol‐1‐yl)‐4‐methylquinolines bearing substituents on the pyrazole 3‐ or 5‐positions (H, Me, Et, i ‐Pr, t ‐Bu) were regioselectively synthesized either using the direct condensation of 2‐chloro‐4‐methylquinoline and sodium salt of 3(5)‐substituted pyrazoles or by treatment of 2‐hydrazino‐4‐methylquinoline with an appropriate β‐ketoaldehyde. The 1 H and 13 C chemical shifts were discussed taking into account the preferred conformation about the C‐2‐N‐1′ bond as calculated by the AM1 Hamiltonian. It appears that 5‐ethyl and 5‐isopropyl substituted derivatives present short C‐H‐N‐1 interactions. Ortho steric effects appear to be responsible for these conformations.